This invention concerns overhead rail systems for conveyor trolleys. A low cost construction previously used has consisted of steel pipe sections welded together, on which run trolleys having sets of angled wheels in engagement with the pipe sides. The steel piping is also sometimes employed as a distribution conduit for compressed air, with welded on fittings provided for connection to air operated tools, hoists, etc.
The use of welded joints makes fabrication difficult as welding must be conducted in the overhead location, and each weld ground smooth to insure that the trolleys will run freely over the joint. Because of the welded construction, it is difficult to reconfigure the systems. Threaded connections for the joints and or operated devices are impractical since if the threads are damaged, an entire rail section may need to be replaced.
The trolleys used also are difficult to remove, as they are captured by the tubing sides, such that they must be run off an end of the rail system, or completely disassembled to be removed. Corrosion of the steel piping is also a problem.
It is an object of the present invention to provide a tubular rail system for overhead conveyors which is easy to install, and which can be easily provided with additional air outlets.